1. Field of the Invention
The present invention relates to a hydrodynamic compression or cutting tool.
2. Description of the Related Art
Hydrodynamic compression and cutting tools are often used to carry out determined connection operations, e.g. compressing connectors about electric wires or for hydraulic pipes, compressing rivets, or for cutting operations, e.g. cutting electric wires during electric system installation and maintenance.
Such tools usually comprise an electric motor supplied by an accumulator and a hydraulic pump which causes an increase of pressure of a hydraulic liquid acting on a piston to move it against the bias of a pressure spring. In turn, the piston is connected to a movable jaw so as to move it during the compression operation towards a fixed jaw of the tool. The jaws may be shaped and/or provided with interchangeable accessory elements so as to adapt to a particular object, e.g. an electric contact to be compressed or a metallic bar to be cut.
The compression or cutting operations are frequently hindered by very narrow space conditions, so that the compression tool acts not only as working head to carry out the compression or cutting operation, but is also an extension of the operator's hand, making it possible to reach working positions either between or behind the other hindering structures. It is thus indispensable for the compression or cutting tools to have a possibly small dimension in direction transversal to the direction of access to the working position. The most known shapes of hand-held hydraulic compression or cutting tools (obviously fixed machine tools installed in stationary manner are not considered here) are pistol-shaped, such as hand-held electric drills, and elongated bar-shaped, such as a torch.
In pistol-shaped tools, the grip extends along a gripping axis and the electric motor, the hydrodynamic pump with the piston for driving the jaws extend along a actuation axis either transversal or perpendicular to the gripping axis. The transversal orientation of the two axes well adapts to the anatomy of the hand without requiring bending of the wrist, but implies a considerable dimension of the tool in direction transversal to the direction of access to the working position, and such transversal dimension is undesirably close to the working head.
In elongated bar-shaped tools, the grip and an electric motor accommodated therein extend along a motor axis, and the hydrodynamic pump and the piston for driving the jaws are coaxial with the same motor axis which constitutes a longitudinal axis of the tool. The coaxial orientation of the motor-gripping group and the pump-actuation cylinder group minimizes the dimension of the tool in direction transversal to the direction of access to the working position so that the tool itself can easily access working positions in even very narrow spaces.
However, the coaxial arrangement of the grip is not completely compatible with the anatomy of the operator's hand and requires an unnatural bending of the wrist in the attempt to align the axis of the actuation piston with the forearm. This undesirably reduces the ergonomics of the tool, increases the fatigue of the musculature of the forearm and of the hand, and implies additional transversal dimensions due to the posture of the operator's hand and arm and not to the tool itself.